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Title: Intercomparison of observed cloud radiative forcing: A zonal and global perspective

Abstract

Despite the general agreement that clouds cool the earth-atmosphere, there are substantial differences in estimated magnitudes of the annual global mean of cloud radiative forcing. Recent estimates of globally averaged net cloud radiative forcing range from [minus]2 to [minus]27 W m[sup [minus]2]. The reasons for these differences have not been clarified in spite of the important role of clouds in maintaining global heat balance. Here, three estimation methods [Earth Radiation Budget Experiment (ERBE), Regression I, and Regression II] are compared using the same data source and analysis period. Intercomparison has been done for the time period of February and March 1985 over which major satellite radiation budget and cloudiness datasets (ERBE radiation budget, Numbus-7, and ISCCP cloudiness) are contemporaneous. The global averages of five sets of net cloud radiative forcing by three independent methods agree to within 3.5 W m[sup [minus]2]; four of five cases agree to within 1 W m[sup [minus]2]. This suggests that differences in published global mean values of net cloud radiative forcing are mainly due to different data sources and analysis periods and a best estimated annual mean among all previous estimates appears to be the ERBE measurement, that is, [minus]17.3 Wm[sup [minus]2]. In contrast tomore » the close agreement in the net cloud radiative forcing estimates, both longwave and shortwave cloud radiative forcing show more dependence on the chosen method and dataset. The bias of regression-retrieved values between Nimbus-7 and ISCCP cloud climatology is largely attributed to the difference in total cloudiness between two climatologies whereas the discrepancies between the ERBE and regression method appear to be, in part, due to the conceptually different definition of clear-sky flux. 32 refs., 5 figs., 2 tabs.« less

Authors:
;  [1]
  1. NASA Marshall Space Flight Center, Huntsville, AL (United States)
Publication Date:
OSTI Identifier:
6146496
Report Number(s):
CONF-930133-
Journal ID: ISSN 0003-0007; CODEN: BAMIAT; CNN: NAS8-37130; NAS8-39231
Resource Type:
Conference
Journal Name:
Bulletin of the American Meteorological Society; (United States)
Additional Journal Information:
Journal Volume: 74:6; Conference: 73. American Meteorological Society (AMS) annual meeting, Anaheim, CA (United States), 17-22 Jan 1993; Journal ID: ISSN 0003-0007
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CLOUDS; ENERGY ABSORPTION; EARTH ATMOSPHERE; RADIATIVE COOLING; GLOBAL ASPECTS; MATHEMATICAL MODELS; METEOROLOGY; REGRESSION ANALYSIS; ABSORPTION; COOLING; MATHEMATICS; SORPTION; STATISTICS; 540110*

Citation Formats

Song, B J, and Robertson, F R. Intercomparison of observed cloud radiative forcing: A zonal and global perspective. United States: N. p., 1993. Web.
Song, B J, & Robertson, F R. Intercomparison of observed cloud radiative forcing: A zonal and global perspective. United States.
Song, B J, and Robertson, F R. 1993. "Intercomparison of observed cloud radiative forcing: A zonal and global perspective". United States.
@article{osti_6146496,
title = {Intercomparison of observed cloud radiative forcing: A zonal and global perspective},
author = {Song, B J and Robertson, F R},
abstractNote = {Despite the general agreement that clouds cool the earth-atmosphere, there are substantial differences in estimated magnitudes of the annual global mean of cloud radiative forcing. Recent estimates of globally averaged net cloud radiative forcing range from [minus]2 to [minus]27 W m[sup [minus]2]. The reasons for these differences have not been clarified in spite of the important role of clouds in maintaining global heat balance. Here, three estimation methods [Earth Radiation Budget Experiment (ERBE), Regression I, and Regression II] are compared using the same data source and analysis period. Intercomparison has been done for the time period of February and March 1985 over which major satellite radiation budget and cloudiness datasets (ERBE radiation budget, Numbus-7, and ISCCP cloudiness) are contemporaneous. The global averages of five sets of net cloud radiative forcing by three independent methods agree to within 3.5 W m[sup [minus]2]; four of five cases agree to within 1 W m[sup [minus]2]. This suggests that differences in published global mean values of net cloud radiative forcing are mainly due to different data sources and analysis periods and a best estimated annual mean among all previous estimates appears to be the ERBE measurement, that is, [minus]17.3 Wm[sup [minus]2]. In contrast to the close agreement in the net cloud radiative forcing estimates, both longwave and shortwave cloud radiative forcing show more dependence on the chosen method and dataset. The bias of regression-retrieved values between Nimbus-7 and ISCCP cloud climatology is largely attributed to the difference in total cloudiness between two climatologies whereas the discrepancies between the ERBE and regression method appear to be, in part, due to the conceptually different definition of clear-sky flux. 32 refs., 5 figs., 2 tabs.},
doi = {},
url = {https://www.osti.gov/biblio/6146496}, journal = {Bulletin of the American Meteorological Society; (United States)},
issn = {0003-0007},
number = ,
volume = 74:6,
place = {United States},
year = {Tue Jun 01 00:00:00 EDT 1993},
month = {Tue Jun 01 00:00:00 EDT 1993}
}

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